1. Field of the Invention
This invention relates to swimming goggles, and more particularly to swimming goggles that are most suitable to competitive swimming.
2. Description of the Related Art
Swimming goggles cover just the eyes and protect the eyes, as well as create a space in front of the eyes and adjust the focal point of the eyes. For human eyes, not having space in front of the eyes makes it impossible to adjust the focal point, and when the eyes are open underwater, everything is blurred and difficult to see.
Typical swimming goggles comprise a pair of eyecups that are connected by a connecting belt, and a belt for wearing the goggles that is fastened between both ends of the eyecups.
The aforementioned pair of eye cups maintains a space in front of each of the eyes, and when worn, are formed of a single piece of transparent plastic such that a flat forward-viewing section that is nearly orthogonal to the direction of the forward line of vision is joined to the forward end section of a cylindrical-shaped peripheral section that extends in the direction of the forward line of vision. By keeping this forward-viewing section at a specified location separated from the eyes by the cylindrical peripheral section, the forward field of vision is in a direction perpendicular to the flat forward-viewing section, which is good. However, when swimming crawl in particular, the eyes are looking upward to look in the direction of swimming. In this case, the field of vision is not in a direction perpendicular to the forward-viewing section, but is at an angle, so the swimmer may sense the light refraction, and it is possible that the field of vision will become poor.
Therefore, the inventors, first proposed swimming goggles having eye cups in which the length of the top part of the peripheral section in the direction of the field of vision was made shorter than the other parts of the peripheral section, and the flat forward-viewing section was such that the top side was tilted in the direction toward the rear of the field of vision. Since the forward-viewing section is tilted, when the eyes are looking upward, the field of vision is in a direction that is perpendicular or nearly perpendicular to the forward-viewing section. Therefore, it is possible to swim without sensing the light refraction or being bothered by the light refraction, thus improving the field of vision.
When wearing these swimming goggles and swimming crawl, the swimmer swims looking forward with the eyes just looking upward, so the field of vision is good. However, when swimming with an up and down motion such as in the breaststroke or butterfly, it is possible that the swimmer will swim looking in both the direction of the forward-viewing section and the direction of the bottom part of the peripheral section. When looking at the forward-viewing section and bottom of the peripheral section at the same time, or when looking at the border between those two sections, the light refraction in the forward-viewing section and the bottom of the peripheral section is different, so what is seen is different. For example, when looking through the bottom of the peripheral section, refracted light is sensed and what is seen appears to be more curved than what is seen from the forward-viewing section. Therefore, two images are seen having different degrees of curvature, and it is possible that the swimmer will begin to feel dizzy or nauseous.